In recent years, automotive vehicles mounted with an auxiliary power supply besides a main battery have been developed for fuel economy improvement and consideration to environments. For example, the amount of power generation by an alternator can be reduced and fuel economy can be improved by accumulating regenerative energy during braking in the auxiliary power supply and using the accumulated energy for the supply of power to electric components during travel. Further, the instantaneous disconnection of the electric components due to an instantaneous voltage drop of the main battery and the deterioration of the main battery can be prevented by supplying power to a starter from the auxiliary power supply when an engine is restarted after an idling stop.
A switching board having a function of switching a power supply mode in correspondence with an operating state of a vehicle such as traveling and an idling stop is disposed between the main battery and the auxiliary power supply in some cases. A switching board used includes a busbar, a switching element mounted on the busbar and a control circuit board (see patent literature 1).
Since a large current flows, a wiring harness having a large outer diameter needs to be used for connection between the switching board and a main battery, an auxiliary battery. It is generally known to connect a wiring harness and a switching board by fixing a fastening terminal connected to one end of the wiring harness to a busbar using a bolt and a nut.
At the time of a fastening operation, after the nut is held by a tool such as an impact wrench, the tool is moved to a fastening position, is positioned with respect to the bolt and fastens the nut. At this time, to avoid the rotation of the fastening terminal according to the rotation of the nut, the fastening operation is normally performed while the fastening terminal is pressed with a tool such as a pair of pliers.
On the other hand, an engine compartment of an automotive vehicle where the switching board is arranged is a narrow space and an operation space is restricted. In such an operational environment, there are problems such as difficulty in aligning the tool for fastening the nut with the fastening position and difficulty in ensuring a clearance for the insertion of the tool for pressing the fastening terminal.
The present invention was completed based on the above situation and aims to provide a switching device capable of improving operability in fixing a fastening terminal.